Absorption transmission and reflection.
Absorption coefficient of hardwood.
Absorption coefficients are an average of how absorptive each product is at numerous frequencies generally at 500 hz 1000 hz and 2000 hz.
In general when sound waves strike on the surface of porous materials sound energy could get channelized as.
Generally speaking soft porous materials will be more absorptive than hard reflective surfaces.
Sound absorption coefficient greater than 1 01 sound absorption coefficient greater than 1 02.
For hackberry hardwood species the better sound absorption coefficient is identified in a wide frequency range of 2 khz 6 khz due to the presence of more pores and larger passageway.
The noise reduction coefficient ranges between 0 40 and 0 75 depending on the slot pattern and installation.
The length and pattern of the slots cut through the panels influence their absorption of soundwaves.
Plywood hardwood panels over 25mm airspace on solid backing 0 30 0 20 0 15 0 10 0 10 0 05 solid backing with absorbent material in air space 0 40 0 25 0 15 0 10 0 10 0 05.
Hardwood burning was identified as the dominant source of carbonaceous aerosols.